Yearly market projections for electronic display devices over the next five to ten years are in the tens of billions of dollars, with $20 billion anticipated in liquid crystal display (LCD) sales alone. In the same timeframe, it is expected that the market for OLEDs will be in the range of $700 million to $3 billion annually.
OLEDs are generally anticipated to overtake LCDs as the preferred display technology. This is expected because OLEDs enjoy a number of practical advantages over LCDs. Some of the most significant advantages include: 1) OLEDs project a brighter image that can be viewed from wider angles; 2) OLEDs do not require the backlight required in LCDs, which lowers the cost of manufacturing, increases reliability of performance, and improves the image intensity range, contrast, and consistency over the viewing area; 3) OLEDs require less power for equivalent image quality; 3) OLEDs are projected to be less expensive to manufacture, requiring fewer materials and roughly half the number of manufacturing steps; 4) OLEDs are designed to have a longer lifetime based on power requirements; and 5) OLEDs produce a wider spectrum of colors.
As a result, manufacturing OLEDs has become an emerging field of interest. As part of the active matrix OLED manufacturing process, circuitry such as organic thin-film transistors (OTFTs) is built on the OLED device to drive the OLED, similar to other display devices. Patterning layers of organic thin film material is one of the specific manufacturing needs to accomplish this. Although the semiconductor industry has developed photolithography and etching methods for silicon wafers, these semiconductor-based methods are not viable for patterning organic materials because (1) the chemistries may be damaging to the organic materials, (2) OLEDs cannot be subjected to semiconductor vacuum processes, and/or (3) the variety of chemistries required for multiple layers may be too expensive to use, or moreover, may not exist. This is particularly true when the substrate in consideration consists of many thin layers of different types of materials. Therefore there exists a need for methods that support fabrication processes and standards for next generation organic electronic devices, for example for flexible displays.
A method of patterning organic layers on a multi-layered structure using multiple chemistry processes is found in U.S. Pat. No. 6,080,529, entitled, “A Method of Etching Patterned Layers Useful as Masking during Subsequent Etching or for Damascene Structures.” However, semiconductor etches and pattern chemistries for patterning multi-layered material both adds process steps, and are expensive. In addition, a specific chemistry is selected to be effective on a specific material, and lacks versatility across multiple layers and substrates. Thus this approach both reduces the overall profitability for manufacturing the device and the ability to use the approach on other materials. Therefore there exists to provide a way to build high quality organic thin film structures, where the materials have been optimized for fabrication through a method that does not require multiple and costly semiconductor etch and pattern chemistries to achieve ablation.
A method of fabricating an electroluminescent (EL) display is found in U.S. patent application Ser. No. 20030186078, entitled “Red-Green-Blue (RGB) Patterning Of Organic Light-Emitting Devices Using Photo-Bleachable Emitters Dispersed in a Common Host.” The '078 patent application describes a method of fabricating organic EL displays with simplified light emitting device (LED) structures. One embodiment of the '078 patent uses a laser ablation technique to ablate away undesired organic and electrode layers patterning discrete RGB pixels adjacent to each other on the same substrate. However, the '078 patent application fails to alleviate some problems with laser ablation techniques on organic thin films. Specifically, the '078 patent application fails to provide a means of optimally selecting thin organic materials taking into consideration each organic layer's differing physical attributes such that the underlying layers are not damaged upon ablation. Therefore there exists a need to provide a way to select materials appropriate for making a layered organic thin film structure, wherein the underlying layers of the structure are not damaged upon patterning of the layers during fabrication.
It is therefore an object of the invention to provide methods that support fabrication processes and standards for next generation organic electronic devices.
It is another object of the invention to provide a way to build high quality organic thin film structures, where the materials have been optimized for fabrication through a method that does not require multiple and costly semiconductor etch and pattern chemistries to achieve ablation.
It is yet another object of the invention to provide a way to select materials appropriate for making a layered organic thin film structure, wherein the underlying layers of the structure are not damaged upon patterning of the layers during fabrication.
It is yet another object of the invention to provide a way of making a multi-layered organic thin film structure, wherein the manufactured structure is patterned at selected and/or multiple layers of the structure.